IDBKeyRange.bound()
The bound()
method of the IDBKeyRange
interface creates a new key range with the specified upper and lower bounds. The
bounds can be open (that is, the bounds exclude the endpoint values) or closed (that
is, the bounds include the endpoint values). By default, the bounds are closed.
Note: This feature is available in Web Workers
Syntax
var myIDBKeyRange = IDBKeyRange.bound(lower, upper);
var myIDBKeyRange = IDBKeyRange.bound(lower, upper, lowerOpen);
var myIDBKeyRange = IDBKeyRange.bound(lower, upper, lowerOpen, upperOpen);
Parameters
- lower
-
specifies the lower bound of the new key range.
- upper
-
specifies the upper bound of the new key range.
- lowerOpen Optional
-
indicates whether the lower bound excludes the endpoint value. The default is false.
- upperOpen Optional
-
Indicates whether the upper bound excludes the endpoint value. The default is false.
Return value
IDBKeyRange
: The newly created key range.
Exceptions
This method may raise a DOMException
of
the following type:
Exception | Description |
---|---|
DataError |
The following conditions raise an exception:
|
Example
The following example illustrates how you'd use a bound key range. Here we declare
a keyRangeValue = IDBKeyRange.bound("A", "F");
— a range between values of
"A" and "F". We open a transaction (using IDBTransaction
) and an object
store, and open a Cursor with IDBObjectStore.openCursor
,
declaring keyRangeValue
as its optional key range value. This means that
the cursor will only retrieve records with keys inside that range. This range includes
the values "A" and "F", as we haven't declared that they should be open bounds. If we
used IDBKeyRange.bound("A", "F", true, true);
, then the range would not
include "A"
and "F"
, only the values between them.
Note: For a more complete example allowing you to experiment with key range, have a look at the idbkeyrange directory in the indexeddb-examples repo (view the example live too.)
function displayData() {
var keyRangeValue = IDBKeyRange.bound("A", "F");
var transaction = db.transaction(['fThings'], 'readonly');
var objectStore = transaction.objectStore('fThings');
objectStore.openCursor(keyRangeValue).onsuccess = function(event) {
var cursor = event.target.result;
if(cursor) {
var listItem = document.createElement('li');
listItem.innerHTML = '<strong>' + cursor.value.fThing + '</strong>, ' + cursor.value.fRating;
list.appendChild(listItem);
cursor.continue();
} else {
console.log('Entries all displayed.');
}
};
};
Specifications
Specification |
---|
Indexed Database API 3.0 # ref-for-dom-idbkeyrange-bound① |
Browser compatibility
BCD tables only load in the browser
See also
- Using IndexedDB
- Starting transactions:
IDBDatabase
- Using transactions:
IDBTransaction
- Setting a range of keys:
IDBKeyRange
- Retrieving and making changes to your data:
IDBObjectStore
- Using cursors:
IDBCursor
- Reference example: To-do Notifications (view example live.)